On the PS5 menu. Highlight the game and press the options button (just right of the touchpad), go to manage content and see if all the levels are installed. If they’re not then you should see an arrow pointing down, and if they are it should just say installed. Make sure everything is installed.
The only other thing I can think to try is restoring your license to the game. Go to Settings, Users and Accounts, Other, Restore Licenses.
Or try rebuilding the PS5 database. Completely turn off the PS5, then hold down the power button, you’ll hear one beep but keep holding it til you hear a second beep. This will boot the PS5 into safe mode. You have to connect your controller using a wire, then select rebuild database.